Path processors are fixated to current request and not the processed request

I just ran across this while working on the GraphQL Module. We are making use of sub-requests to properly resolve contexts from Url objects in our graph. Since our requests all run through /graphql, we have no other option than to use sub-requests to properly set the global contexts used within a variety of internal APIs. The language negotiation, as pointed out by this issue, is one of these and since the request stack is not taken into consideration here, we are always using the negotiated language from the /graphql request which is obviously incorrect.

We solved this temporarily by using the reset() method on the languager manager from within our sub-request.

Adding some tags

Re-rolled patch against 9.4.x. Please review

Re-rolled the patch to be support for the Drupal 9.5.x

Rerolled patch #19 with Drupal 9.5.x

@ankit the patch #19 already works for Drupal 9.5.x not sure why you re rolled it again, please include a interdiff so that we can verify what are the changes.

@arun the patch #16 contained supporting tests which have been removed from your patch.

We had a similar problem but this patch is much to invasive. For example all admin-menu-links got wrong language prefix because of missing currentLanguage.

You are right that AliasPathProcessor::processInbound() does not handle the given request and the given $path is at this point without language prefix:

 public function processInbound($path, Request $request) {
    $path = $this->aliasManager->getPathByAlias($path);
    return $path;
  }

But the called function getPathByAlias() has an 2nd paramater for language. So you can use:

  public function processInbound($path, Request $request) {
    // Get language from request.
    $lang = \Drupal::service('language_negotiator')->getNegotiationMethodInstance('language-url')->getLangcode($request) ?? NULL;

    $path = $this->aliasManager->getPathByAlias($path, $lang);
    return $path;
  }

Now you can get the path by alias in other languages than current.

Maybe you will try the patch in combination with your tests.

I did test locally with this code:

use Symfony\Component\HttpFoundation\Request;

$pathProcessor = \Drupal::service('path_processor_manager');
$path_de = '/de/lang-de-test';
$path_en = '/en/lang-en-test';

$request = Request::create($path_de);
$processedPath = $pathProcessor->processInbound($path_de, $request);
dpm($processedPath);

$request = Request::create($path_en);
$processedPath = $pathProcessor->processInbound($path_en, $request);
dpm($processedPath);

If you have trouble with fixed "getCurrentLanguage()" (e.g. for language sensitive access checks) then you have to reset() the languageManager and use the requestStack in this situations. But in general - like in this patch suggested - seems to be too much.

Tried this to fix #2801397 with no luck. Here's a reroll of the patch in #21 on main in case it is of interest to someone. Not changing the status since I was not trying to fix this issue.